Control of a video tape recorder or video disc player by a host computer has been accomplished in the prior art by providing the host computer with a dedicated I/O port connected by a appropriate cable and connector to the video equipment. Not only has this required separate I/O boards for equipment providing control signals every frame and equipment providing two control signals per frame, but different manufacturer's equipment employ different connectors and even the same manufacturer's equipment, when employing the same connector, may employ different pins of the connector for the same control function in different models.
Furthermore, new equipment continues to be available at a rapid pace. This new equipment often requires different connections and different forms of control signals. Home video equipment, for example, utilizes matrix signaling, that is pairs of row and column lines are pulsed or grounded to indicate a particular signal. The manufacturers of the newer video disc equipment have already stated that there will be radical changes in their equipment in the immediate future. Thus, according to the prior art, the ability to interface a host computer to a wide variety of video equipment requires multiple I/O boards, multiple cables, multiple connectors, etc., and is very expensive.